Stimulation of a postsynaptic neuron by many terminals at the same time.

Subthreshold stimulus

An insufficient stimulus.

Threshold stimulus

Any stimulus below this intensity will result in no response in a neuron.

trigger zone

Area where nerve impulse is generated.

receptive region

Receives stimuli.

conducting region

Plasma membrane exhibits voltage-gated Na+ and K+ channels.

secretory region

Plasma membrane exhibits voltage-gated Ca2+ channels.

secretory zone

Axon terminals release neurotransmitters.

receptive region

Plasma membrane exhibits chemically gate ion channels.

diverging circuit

One incoming fiber triggers responses in ever-increasing numbers farther and farther along the circuit.

parallel after-discharge circuit

May be involved in complex, exacting types of metal processing.

reverberating circuit

Involved in control of rhythmic activities such as breathing.

diverging circuit

Involved in activating fibers of a skeletal muscle such as the biceps muscle.

converging circuit

Different types of sensory input can have the same ultimate effect.

histamine

Increases acid secretion in the stomach; blocked by cimetidine.

norepinephrine

"Feel-good" neurotransmitter.

substance p

Mediates pain.

glycine

Principal inhibitory neurotransmitter of the spinal cord.

endorphins

Natural opiates that inhibit pain; effect mimicked by morphine.

E. provide the defense for the CNS

Which of the following is NOT a function of astrocytes?A. support and brace neuronsB. anchor neurons to blood vesselsC. guide the migration of young neurons, synapse formation, and helping to determine capillary permeabilityD. control the chemical environment around neuronsE. provide the defense for the CNS

motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle and glands

Describe the ANS.

ependymal cells

What are ciliated CNS neuroglia that play an active role in moving the cerebrospinal fluid?

The period after an initial stimulus when a neuron is not sensitive to another stimulus.

c. they are mitotic

Which of the following is NOT a special characteristic of neurons?A. they conduct impulsesB. they have extreme longevityC. they are mitoticD. they have an exceptionally high metabolic rate

axon

The part of a neuron that conducts impulses away from its cell body.

voltage-gated channel

An ion channel that opens in response to a change in membrane potential and participates in the generation and conduction of action potentials.

synapse

An impulse from one nerve cell is communicated to another nerve cell via the ___.

destroy ACh a brief period after its release by the axon endings

What is the role of acetylcholinesterase?

D. innervation of skeletal muscle

Which of the following is NOT a function of the autonomic nervous system?a. innervation of smooth muscle of the digestive tractb. innervation of cardiac musclec. innervation of glandsd. innervation of skeletal muscle

ganglia

Collections of nerve cell bodies outside the central nervous system.

neurotransmitter

The substance released at axon terminals to propagate a nervous impulse.

association neuron

A neuron that has as its primary function the job of connecting other neurons.

the myelin sheath

Saltatory conduction is made possible by ___.

e. nucleic acid

Which of the following is NOT a chemical class of neurotransmitters?a. acetylcholineb. amino acidc. biogenic amined. ATP and other purinese. nucleic acid

b. a nerve impulse occurs if the excitatory in inhibitory effects are equal

Which of the following is false or incorrect?a. an excitatory postsynaptic potential occurs if the excitatory effect is greater than the inhibitory effect but less than threshold.b. a nerve impulse occurs if the excitatory in inhibitory effects are equal.c. an inhibitory postsynaptic potential occurs if the inhibitory effect is greater than the excitatory, causing hyper polarization of the membrane.

d. the synaptic cleft prevents an impulse from being transmitted directly from one neuron to another

Select the correct statement regarding synapses.a. cells with interconnected cytoplasm are chemically coupledb. the release of neurotransmitter molecules gives cells the property of being electrically coupledc. neurotransmitter receptors are located on the axons of cellsd. the synaptic cleft prevents an impulse from being transmitted directly from one neuron to another

help to circulate the cerebrospinal fluid

Ependymal cells ___.

astrocytes

Neuroglia that control the chemical environment around neurons by buffering potassium and recapturing neurotransmitters.

oligodendrocytes

Schwann cells are functionally similar to ___.

potassium

Immediately after an action potential has peaked, which cellular gates open?

are crucial for the development of neural connections

Nerve cell adhesion molecules (N-CAMs) ____.

hyperpolarization

An inhibitory postsynaptic potential (IPSP) is associated with ____.

a single type of channel will open, permitting simultaneous flow of sodium and potassium

What occurs when an excitatory postsynaptic potential (EPSP) is being generated on the dendritic membrane?

generator potential

When a sensory neuron is excited by some form of energy, the resulting graded potential is called a(n) ___.

c. they increase amplitude as they move away from the stimulus point

Which of the following is not true of graded potentials?a. they are short-livedb. they can form on receptor endingsc. they increase amplitude as they move away from the stimulus pointd. they can be called postsynaptic potentials

b. some ions are prevented from moving down their concentration gradients by ATP-driven pumps

Which of the following is true about the movement of ions across excitable living membranes?a. ions always move actively across membranes through leakage channelsb. some ions are prevented from moving down their concentration gradients by ATP-driven pumpsc. sodium gates in the membrane can open in response to electrical potential changesd. the bulk of the solutions inside a cell are negatively charged

the membrane potential has been reestablished

A second nerve impulse cannot be generated until ___.

the interior is negatively charged and contains less sodium

In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment?

the impulse would spread bidirectionally

If a motor neuron in the body were stimulated by an electrode placed about midpoint along the length of an axon...

group c fibers are not capable of saltatory conduction

How are group c neuron fibers classified?

spinal reflexes

What is an example of serial processing?

somatic

That part of the nervous system that is voluntary and conducts impulses from the CNS to the skeletal muscles is the ___ nervous system.

astrocytes

___ are found in the CNS and and bind axons and blood vessels to each other.

node of ranvier

A gap between Schwann cells in the peripheral system.

ATP-dependent "motor" proteins such as kinesin, dynesin, and myosin.

What mechanism is responsible for axon transport?

electrical synapse

The synapse more common in embryonic nervous tissue than adults is the ___.

parallel processing

When information is delivered within the CNS simultaneously by different parts of the neural pathway.

graded

___ potentials are short-lived, local changes in membrane potential that can be either depolarized or hyper polarized.

multiple sclerosis

___ is a disease that gradually destroys the myelin sheaths of neurons in the CNS, particularly in young adults.

temporal

When one or more presynaptic neurons fire in rapid order it produces a much greater depolarization of the postsynaptic membrane than would result from a single EPSP; this event is called ___ summation.

Foramen magnum

The spinal cord begins at the level of the

Cauda equina

The nerves arising from the inferior lumbosacral enlargement form the

Subarachnoid space

What area of the spinal cord contains cerebrospinal fluid?

Filum terminale and denticulate ligaments

What structures help to anchor the spinal cord within the subarachnoid space?

Three horns

The gray matter of each halve of the spinal cord is divided into

Sensory and has a ganglion

The dorsal spinal nerve root is

Lateral gray horns

The cell bodies of motor neurons to autonomic effectors are located in the

Withdrawal

Pulling the arm back from a hot pan is an example of a ______ reflex.

Endoneurium

The connective tissue wrap around an axon and its Schwann cell sheath is the

Perineurium

The connective tissue wrap that surrounds many axons to form a fascicle is the

Epineurium

The connective tissue wrap the surrounds many fascicles to form a nerve is the

Which of the following is NOT a main nerve of the brachial plexus? A. Median, B. Phrenic, C. Musculocutaneous, D. Ulnar, E. Radial

Cervical

The phrenic nerve is the major nerve from the ______ plexus.

Anterior thigh and leg

The major nerves from the lumbar plexus serve the

Sacral

The sciatic nerve comes from the _________ plexus.

A. Thalamus

Which of the following is NOT part of the brainstem? A. Thalamus / B. Pons / C. Medulla oblongata / D. Midbrain

B. Auditory relay center

Which of the following is NOT a function of the medulla oblongata? A. Regulate heart rate / B. Auditory relay center / C. Regulate blood vessel diameter /D. Regulate breathing

D. Visual relay center

Which of the following is NOT a function of the pons? A. Controls chewing and salivation / B. Aides the medulla oblongata in controlling breathing, swallowing and balance / C. Relay between the cerebellum and cerebrum / D. Visual relay center

Reticular activating system

What structure plays a major role in consciousness and sleep-wake cycles?

Arbor vitae

The white matter of the cerebellum is called the

C. Origin of impulses to skeletal muscle

Which of the following is NOT a function of the cerebellum? A. Controls balance and eye movements / B. Controls posture, locomotion and fine motor coordination / C. Origin of impulses to skeletal muscle / D. Planning, practicing and learning complex movements

B. Midbrain

Which of the following is NOT part of the diencephalon? A. Hypothalamus / B. Midbrain / C. Thalamus / D. Subthalamus

Thalamus

All sensory impulses except for smell are relayed through the

D. Control of the autonomic nervous system

Which of the following is NOT a function of the thalamus? A. Regulation of skeletal muscles / B. Limbic system and emotions / C. Perception of pain / D. Control of the autonomic nervous system

Habenular

What part of the diencephalon is involved with emotional and visceral responses to odors?

D. All of the choices are correct

Which of the following is NOT a function of the hypothalamus? A. Body temperature control / B. Autonomic nervous system control / C. Mood and emotions / D. All of the choices are correct

Mammillary bodies

What part of the hypothalamus are involved in emotional responses to odors, olfactory reflexes and memory?

Longitudinal fissure

What divides the cerebrum into right and left hemispheres?

Central

What structure separates the frontal from the parietal lobe?

Cerebral medulla

The white matter of the cerebrum is the

Commissural fibers

What type of fibers connect one hemisphere to the other?

Projection fibers

What type of fibers are continuations of the fibers in the spinal cord?

The _______________ neuron runs from the CNS and the autonomic ganglion.

Thoracolumbar division

Another name for the sympathetic division is the

Lateral gray horns of T1 through L2 region of the spinal cord

The cell bodies of the sympathetic preganglionic neurons are in the

Alongside the vertebral column from cervical through sacral regions

The sympathetic chain ganglion are located

Short and myelinated and the postganglionic neuron is long and nonmyelinated

In the sympathetic division, the preganglionic neuron is

Skeletal muscle B. Smooth muscle and glands in the skin

Sympathetic postganglionic nerves that run with spinal nerves will serve

Organs in the thoracic cavity

Sympathetic postganglionic nerves that form sympathetic nerves supply

Organs in the abdominal cavity

The sympathetic splanchnic nerves serve

Adrenal medulla

Splanchnic nerves that do not synapse in either the chain ganglion nor the collateral ganglion will synapse with specialized neurons in the

Brain stem and lateral gray horns of the sacral area of the spinal cord

The cell bodies of the parasympathetic preganglionic neurons are found in the

Long and myelinated and the postganglionic neuron is short and nonmyelinated

In the parasympathetic division, the preganglionic neuron is

C. Somatic motor neurons that connect the CNS to the digestive tract

The nerve plexuses of the enteric nervous system receive contributions from all of the following except A. Enteric neurons of the enteric plexuses / B. ANS neurons that connect the CNS to the digestive tract / C. Somatic motor neurons that connect the CNS to the digestive tract / D. Sensory neurons that connect the digestive tract to the CNS

Norepinephrine

Nerve fibers that are considered adrenergic secrete ____ as the neurotransmitter.

Nicotinic receptors

Cholinergic receptors on skeletal muscles and postganglionic neurons in the ANS are called

Muscarinic receptors

Cholinergic receptors on ANS effectors are called

Inhibitory or excitatory

Acetylcholine binding to muscarinic receptors has a/an ______ effect, depending on the effector.

Alpha or beta receptors

Adrenergic receptors on effectors are called

C. All sympathetic postganglionic neurons

Which of the following does NOT release acetylcholine? A. All sympathetic preganglionic neurons / B. All parasympathetic preganglionic neurons / C. All sympathetic postganglionic neurons / D. All parasympathetic postganglionic neurons

D. Blood vessels

Which of the following effectors are NOT cholinergic? A. Sweat glands / B. Heart / C. Large intestines / D. Blood vessels

A sudden increase in blood pressure detected by baroreceptors in the walls of large arteries near the heart will cause

Sympathetic

In general, stimulation of the posterior hypothalamus produces ____ responses.

Arrector pili muscle

Which organs receive sympathetic innervation, but NOT parasympathetic?

Dilate the pupil

What is the function of the sympathetic division?

Constriction of airways

What is the function of the parasympathetic division?

Increase digestive functions

In general, the parasympathetic division will

Sympathetic

Which division of the ANS has a more generalized effect in the body?

One preganglionic neuron synapses with many postganglionic neurons; The secretion of epinephrine and norepinephrine can effect many organs

Why does the sympathetic division of the ANS have a more generalized effect in the body?

C. Increased secretions in the digestive tract

Which of the following is NOT a typical "flight or fight" response by the sympathetic division of the ANS? A. Vasoconstriction of abdominal blood vessels / B. Dilation of air passageways / C. Increased secretions in the digestive tract / D. Increased fat break down for energy

Calcium and sodium

What ion channels are opened to produce an action potential in olfactory neurons?

comprised of the cerebral peduncles, corpora quadrigemina, and substantia nigra

long-term memory

allows the memorization of potentially limitless amounts of information for very long periods

a high emotional state, repetition, association of new information with old, or the automatic formation of memory while concentrating on something else.

transfer of information from short-term to long-term memory can be affected by

declarative memory

entails learning explicit information, is often stored with the learning context, and is related to the ability to manipulate symbols and language.

nondeclarative memory

entails motor skills, is often stored without details of the learning context, and is reinforced through performance.

learning

causes changes in neuronal RNA, dendritic branching, deposition of unique proteins at LTM synapses, increase of presynaptic terminals, increase of neurotransmitter, and development of new neurons in the hippocampus.

in this reflex, the muscle spindle is stretch and excited by either an external stretch or an internal stretch.

golgi tendon reflex

produces muscle relaxation and lengthening in response to contraction

flexor (withdrawal) reflex

initiated by a painful stimulus and causes automatic withdrawal of the threatened body part from the stimulus

crossed-extensor reflex

a complex spinal reflex consisting of an ipsilateral withdrawal reflex and a contralateral extensor reflex

superficial reflexes

elicited by gentle cutaneous stimulation

the developing spinal cord and adjacent neural crest

the spinal nerves branch from

the forming vertebrae

the spinal nerves exit between

cranial nerves

innervate muscles of the head in a similar way

sensory receptors

atrophy to some degree with age, and there is a decrease in muscle tone in the face and neck; reflexes occur a bit more slowly

vision

our dominant sense

70%

what percent of our body's sensory receptors are found in the eye

eyebrows

short, coarse hairs overlying the supraorbital margins of the eye that shade the eyes and keep perspiration out

eyelids (palpebrae), eyelashes, and their associated glands

help to protect the eye from physical danger as well as from drying out

conjunctiva

a transparent mucous membrane that lines the eyelids and the whites of the eyes

conjunctiva

produces a lubricating mucus that prevents the eye from drying out

lacrimal apparatus

consists of the lacrimal gland, which secretes a dilute saline solution that cleanses and protects the eye as it moistens it, and ducts that drain excess fluid into the nasolacrimal duct

the movement of each eyeball

controlled by six extrinsic eye muscles that are innervated by the abducens and trochlear nerves

3

how many layers form the wall of the eyeball?

fibrous tunic

the outermost coat of the eye and is made of a dense avascular connective tissue

sclera and cornea

two regions of the fibrous tunic

vascular tunic (uvea)

the middle layer of the eyeball

choroid, ciliary body, iris

three regions of the vascular tunic

retina

the inner layer of the eye

outer pigmented layer, inner neural layer

two regions of the retina

outer pigmented layer

region of the retina that absorbs light

inner neural layer

region of the retina that contains millions of photoreceptors (rods, cones) that transduce light energy

posterior segment (cavity)

filled with a clear gel called vitreous humor that transmits light, supports the posterior surface of the lens, holds the retina firmly against the pigmented layer, and contributes to intraocular pressure

anterior segment (cavity)

filled with aqueous humor that supplies nutrients and oxygen to the lens and cornea while carrying away wastes

lens

an avascular, biconcave, transparent, flexible structure that can change shape to allow precise focusing of light on the retina

electromagnetic radiation

includes all energy waves from long waves to short waves, and includes the visible light that our eyes see as color

refraction of a light ray

occurs when it meets the surface of a different medium at an oblique angle rather than a right angle

three

how many times is light bent when entering/leaving the cornea and lens?

far point of vision

that distance beyond which no change in lens shape is required (about 6 meters or 20 feet)

accommodation of the lens, constriction of the pupils, and convergence of the eyeballs

three adjustments demanded by the focusing for close vision

myopia (nearsightedness)

occurs when objects focus in front of the retina and results in seeing close objects without a problem but distant problems are blurred

hyperopia (farsightedness)

occurs when objects are focused behind the retina and results in seeing distant objects clearly but close objects are blurred

photoreception

the process by which the eye detects light energy

photoreceptors

modified neurons that structurally resemble tall epithelial cells

rods

highly sensitive and are best suited to night vision

cones

less sensitive to light and are best adapted to bright light and color vision

photoreceptors

contain a light-absorbing molecule called retinal

rhodopsin

the visual pigment of rods, formed and broken down within the rods (same for cones)

pigment breakdown

exposure of the photoreceptors to light causes

light adaptation

occurs when we move from darkness into bright light

dark adaptation

occurs when we go from a well-lit area into a dark one

retinal ganglion cells

merge in the back of the eyeball to become the optic nerve, which crosses at the optic chiasma to become the optic tracts

optic tracts

send their axons to neurons within the lateral geniculate body of the thalamus

axons from the thalamus

project through the internal capsule to form the optic radiation of fibers in the cerebral white matter

visual processing

occurs when the action of light on photoreceptors hyper polarizes them, which causes the bipolar neurons from both rods and cones to ultimately send signals to their ganglion cells

receptors for taste and smell

chemoreceptors that respond to chemicals in solution

olfactory epithelium

the organ of smell located in the roof of the nasal cavity

olfactory receptors

bipolar neurons with a thin apical dendrite that terminates in a knob with several olfactory cilia

volatile, and it must be dissolved in the fluid coating the olfactory epithelium that stimulates the olfactory receptors

to smell a particular odorant, it must be

olfactory transduction

an odorant binds to the olfactory receptor, a g protein, and the secondary messenger of cyclic AMP.

taste buds

the sensory receptor organs for taste

taste buds

located in the oral cavity, with the majority located on the tongue

sweet, sour, bitter, salty, umami

five basic taste sensations

dissolved in saliva, move into the taste pore, and contact a gustatory hair

for a chemical to be tasted it must be

taste sensation

each has its own special mechanism for transduction

afferent fibers carrying taste information from the tongue

found primarily in the facial nerve and glossopharyngeal cranial nerves

vagus nerve

taste impulses from the few taste buds found on the epiglottis and the lower pharynx are conveyed via the

taste

strongly influenced by smell and stimulation of thermoreceptors, mechanoreceptors, and nociceptors.

anosmias

olfactory disorders resulting from head injuries that tear the olfactory nerves, nasal cavity inflammation, or aging.

uncinate fits

olfactory hallucinations

taste disorders

less common but may be caused by respiratory tract infections, head injuries, chemicals, medications, or head and neck radiation.

auricle (pinna) and the acoustic meatus

the external ear consists of the

middle ear (tympanic cavity)

a small, air-filled, mucosa-lined cavity in the petrous portion of the temporal bone; spanned by the auditory ossicles

bony labyrinth, membranous labyrinth

two divisions of the internal ear

vestibule

central cavity of the body labyrinth with two membranous sacs suspended in the perilymph, the saccule and the utricle

semicircular canals

project from the posterior aspect of the vestibule, each containing an equilibrium receptor region called a crista ampullaris

spiral, snail-shaped cochlea

extends from the anterior part of the vestibule and contains the cochlear duct

cochlear duct

houses the spiral organ (of corti), the receptors for hearing

sound

a pressure disturbance produced by a vibrating object and propagated by the molecules of the medium

processes sound signals mechanically before they ever reach the receptors

transduction of sound stimuli

occurs after the trapped stereo cilia of the hair cells are deflected by localized movements of the basilar membrane

perception of pitch, detection of loudness, and localization of sound

auditory processing involves

deafness

any hearing loss, no matter how slight

tinnitus

a ringing or clicking sound in the ears in the absence of auditory stimuli

meniere's syndrome

a labyrinth disorder that causes a person to suffer repeated attacks of vertigo, nausea, and vomiting

equilibrium sense

responds to various head movements and depends on input from the internal ear, vision, and information from stretch receptors of muscles and tendons

maculae

sensory receptors for static equilibrium

crista ampullaris

receptor for dynamic equilibrium

crista ampullaris

found in the ampulla of the semicircular canals and activated by head movement

directly to reflex centers in the brain stem

information from the balance receptors goes ___________________________, rather than to the cerebral cortex.

somatic nervous system

stimulates skeletal muscles

autonomic nervous system

innervates cardiac an smooth muscle and glands

somatic nervous system

the cell bodies of the neurons are in the spinal cord and their axons extend to the skeletal muscles they innervate

autonomic nervous system

consists of a two-neuron chain

acetylcholine

neurotransmitter released by the somatic motor neurons

epinephrine and acetylcholine

neurotransmitters released by the autonomic nervous system; both may have either an excitatory or an inhibitory effect

overlap

there is _____ between the somatic and autonomic nervous systems

skeletal muscle activity and visceral organ responses

most body responses to changing internal and external stimuli involve both ____ and ____

parasympathetic division

keeps body energy use as low as possible while directing digestion and elimination activities

sympathetic division

prepares the body to respond to an energy or threatening situation (or vigorous exercise)

preganglionic axons

extend from the CNS nearly all the way to the structures to be innervated, where they synapse with ganglionic neurons in the terminal ganglia

cranial outflow

consists of preganglionic fibers that run in the oculomotor, facial, glossopharyngeal, and vagus cranial nerves

sacral outflow

the rest of the large intestine and pelvic organs are served by the

sacral outflow

arises from neurons located in the lateral gray mater of the spinal cord segment S2-S4

sympathetic division

supplies the visceral organs in the internal body cavities but also all visceral structures in the somatic part of the body

gray rami communicantes

when synapses are made in chain ganglia, the postganglionic axons enter the ventral (or dorsal) ramus of the adjoining spinal nerves by way of communicating branches called

preganglionic fibers from t5 down

enter and leave the sympathetic chains without synapsing

thoracic splanchnic nerves; adrenal cortex

some fibers of the ___________ terminate by synapsing with the hormone-producing medullary cells of the _________.

visceral sensory neurons

the first link in autonomic reflexes, sends information concerning chemical changes, stretch, and irritation of the viscera

B. sensory neuron-delivers signals to control sensory organs such as eye movement

Which is NOT a correct association of structure and function?A. axons-outgoing signalsB. sensory neuron-delivers signals to control sensory organs such as eye movementC. cell body-nucleus and organellesD. dendrites-incoming signalsE. interneuron-sums up input before sending signals to muscle or gland

dendrites

carry impulses toward a cell body

the nerve contained both sensory and motor neurons

carpal tunnel results in damage to one medial nerve that results in lack of control to the wrist and also numbness. this indicates that

axons

When a finger or other appendage is severed in an accident, it is possible to surgically rejoin most tissues (bone, skin, etc.) and most will grow back together. However, in a cut through an appendage nerve, it is currently more difficult to reconnect what are primarily severed _____.

away from the cell body

in the axon, the nerve impulses travel

they are mostly myelin sheath made of lipid or fat molecules

in dissection, most nerve fibers appear gray to white because

e. cell walls

which of the following does not pertain to neurons?a. sodium pumpsb. schwann cellsc. myelind. nodes of rangiere. cell walls

d. it decreases the speed of nerve impulse conduction

which of the following is not true about the myelin sheath?a. it is composed of layers of cellular membrane containing myelin around nerve fibersb. it gives nerve fibers their white glistening appearancec. it provides a pathway for new fiber growth if the axon is severedd. it decreases the speed of nerve impulse conductione. it is formed from schwann cells

nerve impulse

a change in the difference in positive and negative ions on the outer and inner surfaces of the neuron membrane, a change that opens adjacent channels and propagates its flow

the action potential jumps from node to node

"Saltatory" conduction occurs when

the speed with which sodium ion can be pumped back outside the neuron membrane

how fast a person can type or play the piano is ultimately limited by the number of impulses a person can send to their fingers per second. this in turn is limited by

synaptic vesicles fuse with the presynaptic membrane, and neurotransmitters diffuse across the synaptic cleft

in order for transmission across the synapse to occur

either excite or inhibit the postsynaptic neuron

neurotransmitters are molecules that cross the synaptic cleft and

acetylcholine

the enzyme that breaks down acetylcholine within the synaptic cleft is

e. cholinesterase

which of the following is not a neurotransmitter?a. gabab. norepinephrinec. acetylcholined. dopaminee. cholinesterase

both sensory and motor fibers

spinal nerves contain

reflex actions and communication between the brain and spinal nerves

the primary functions of the spinal cord involve

nerve

composed of the long fibers of long axons

reflex action

an automatic, involuntary response

motor neuron

part of a simple relax that takes the message away from the CNS

tracts

bundles of nerve fibers traveling up or down the white matter of the spinal cord

cauda equina

bundle of nerve roots within vertebrae L2-S5 which innervate the pelvic organs and legs

dorsal horn

all somatic sensory fibers from the neck down enter a region of gray matter of the spinal cord called the

sciatic

the thick ___ nerve of the lower limb is actually two nerves enclosed in a common fibrous sheath

dura mater

this meninx lies closest to the surrounding bone

afferent fibers

nerve fibers that conduct sensory signals to the central nervous system

name of a type of nerve that transmits both sensory and motor information

reflexes

coordinators of simple, repeated actions

neurilemma

an individual peripheral nerve axon is covered by Schwann cells which produce a

somatic

nerve fibers that innervate the skin and skeletal muscles

the ventral horn of the spinal cord

the upper motor neurons that control the skeletal muscles are found in

coticospinal tracts

the signals that control you handwriting travel down the spinal cord in

the dorsal horns of the spinal cord

most lower motor neurons are located in

adipose tissue

the epidural space in the spinal column is occupied by

endoneurium

the neurilemma is covered by the loose connective tissue called the

b. touch

which of the following sensory functions involve neurons in the dorsal root ganglia?a. smellb. touchc. hearingd. tastee. vision

the ventral horn of the spinal cord

nerve fibers that stimulate the skeletal muscles of your foot have their somas in

phrenic nerves

if the ___ of the cervical plexus were severed, it would have a life-threatening effect, whereas severance of any other would be less serious.

sciatic nerve

two nerves inclosed in a common fibrous sheath

cervical, thoracic, lumbar, sacral

the spinal cord is divided into what regions

coccygeal ligament

this structure anchors the spinal cord to L2

intercostal nerve

most important in relaying motor signals bringing about ventilation

chickenpox

this viral infestation can remain viable with the dorsal root ganglia for many years

cervical

sensory only nerve

central pattern generators

walking is controlled by groups of neurons in the spinal cord called

L1

spinal cord ends at about which vertebra?

lumbar

nerves to the pelvic region and lower limbs arise from an area of the spinal cord called the

cauda equina

a bundle of nerve roots that occupy the canal of vertebrae L2 to S5

epidural

anesthetics and anti-inflammatory drugs are introduced into this space in the spinal cord

subarachnoid space

majority of cerebrospinal fluid in the spinal cord is found here

pia matter

the innermost meninx around the spinal cord

terminal filum

the pia matter extends beyond the medullary cone as

spina bofida

a congenital defect resulting from the failure of one or more vertebrae to form a complete vertebral arch for enclosure of the spinal cord

epidural space, dura matter, arachnoid, subarachnoid space

you were going to have a spinal tap to remove some cerebrospinal fluid for analysis. starting from outside of the spinal cord, what would be the correct order of spaces and meninges through which the syringe would pass?

you are following the signals from a sensory neuron to the spinal cord where it synapses with a motor neuron that leaves the spinal cord and synapses on a skeletal muscle the route would be

gracile fasciculus; medulla oblongata

sensory information about deep touch or visceral pain in the lower limbs are carried in ____ tracts, which decussate, or cross over, in the _____.

thalamus

second-order neurons synapse with neurons in the

amyotrophic lateral sclerosis

this disease is marked by degeneration of motor neurons, and in most cases, neurons are destroyed by the inability of astrocytes to reabsorb glutamate, which allows this neurotransmitter to reach toxic levels

this virus remains for life in the dorsal root ganglion but can travel down neurons from the dorsal root ganglion by fast axonal transport and cause a painful trail of skin discoloration along the path of the neurons. this virus travels down ____ neurons and causes ____.

sacral; lumbar

the sciatic nerve comes from the ___ plexus, while the femora nerve comes from the ____ plexus

stretch reflex

you begin to nod off as you are reading this question. your head starts to lower a bit but this reflex causes your head to rise

above level c5

quadriplegia, or paralysis of all four limbs, results from spinal cord lesions

brain; spinal cord

the central nervous system consists of the ___ and ___.

neuroglia

nervous tissue is composed of neurons and supporting cells called ___.

threshold

whether or not a neuron fires depends on whether it is depolarized to a voltage called its ___.

nodes of ranvier

in the peripheral nervous system, myelin sheaths have gaps called ___ about 1 mm apart.

synapse

the junction where one neuron meets another

all-or-none

neurons follow the ___ law, meaning they either fire at a maximum voltage or not at all

dendrite

the portion of the neuron that receives signals from other neurons

alzheimer disease

neurofibrillary tangles and the destruction of parts of the hippocampus are characteristics of

norepinephrine

a neurotransmitter whose function depends on a second messenger

microglia

macrophages of the central nervous system

glycine

an inhibitory neurotransmitter is known as

synapse

the gap between one neuron and the next

oligodendrocytes

the brain's counterpart to the schwann cells

summation

the process of adding up postsynaptic potentials and responding to their net effect

facilitation

process in which one presynaptic neuron makes it easier for another one to stimulate a postsynaptic neuron

soma

nissl bodies are located in the ____ of a neuron

axon hillock

the trigger zone of a neuron includes

diverging

in a ___ neuronal circuit, input to one neuron leads to output from multiple neurons

voltage-regulated Na+ gates open

when a neuron is depolarized to threshold

endoneurium

because of the absence of an _____, damaged nerve fibers in the CNS cannot regenerate.

nerve signals pass from neuron to neuron over junctions called synapses

the neuron doctrine refers to the fact that

diverging circuits

because of ___, one motor neuron of the brain can ultimately cause thousands of muscle fibers to contract

axon hillock

summation occurs in the ____ of a neuron

nerve signals

travel fastest in large myelinated fibers

endothelium

the blood brain barrier consists of tight junctions in the

help form the blood brain barrier

one role of the astrocytes is to

ependymal cells

____ line the ventricles of the brain

gland

an effector

interneurons

the integrative function of the nervous system i associated especially with

central

the brain and spinal cord constitute the ___ nervous system

the threshold potential

a neuron fires only when its membrane reaches

substance p

long-term memories occur when there are more of these receptors

na+ is entering the neuron

during the rising phase of an action potential

neurilemma

the bodies of the schwann cells

self-propogating

unlike local potentials, action potentials are

calcium ions enter the synaptic knob

the first event when a nerve reaches a synaptic knob

astrocytes

blood capillaries of the brain are enveloped by

rough endoplasmic reticulum

the nissl bodies of a neuron consist of

one axon and one dendrite arising from the soma

a bipolar neuron has

+35 mv

a typical neuron will have a membrane voltage of about ___ at the time when sodium gates close and potassium ions begin rapidly leaving the cell.

with their nerve cell bodies in the PNS and their synaptic knobs in the CNS

unipolar neurons are found

undergo mitosis

mature neurons lack centrioles. you would expect these neurons to be unable to

astrocyte

the most abundant cell in the nervous system

central nervous system; form the myelin sheath

the oligodendrocyte is found in the ___ and functions to ___________.

astrocytes

the glial cells that contribute to the blood-brain barrier in the CNS

had been damaged by infection, trauma, or stroke

in an autopsy, a pathologist found an area of brain tissue with very high concentration of microglia. that area of the brain most likely

ependymal cells

glial cells which resemble a cuboidal epithelium without the basement membrane and produce cerebrospinal fluid (CSF)

glial cells; blood-brain barrier

most adult brain tumors are composed of ____ cells and cannot be treated by chemotherapy because of the _____.

large; myelinated

neurons that send impulses to skeletal muscles have a ____ diameter and are ____.

multiple sclerosis

in this disorder, oligodendrocytes and myelin sheaths of the CNS deteriorate and are replaced by hardened scar tissue

dopamine

parkinson's disease is caused by degeneration of neurons that release

serotonin

prozac (fluoxetine) is an antidepressant that blocks the synaptic reuptake of